<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./jquery-2.1.4/jquery.js"></script>
</head>
<body>
<input type="text" id="txt1" value="测试">
<input type="button" id="btn1" value="点我">
<script>
    $(function () {
        $("#btn1").click(function () {
//            console.log($("#txt1")) ;
//           console.log($("#txt1").text()) ;
//            console.log($("#txt1").html()) ;
//            console.log($("#txt1").value) ;
//            console.log($("#txt1").val()) ;

        })
    })
</script>
</body>
</html>